Quadratic Graphs

Quadratic graphs sound hard…but they’re not really! They are simply just graphs in this format:

  • y = x+ anything

To plot a quadratic graph just put in a load of y values, and get the corresponding x values.

Once you have enough coordinates (usually about 9) you can draw the graph.

NOTE: it will be a smooth curve – if one point goes off you have made a mistake!

Here’s an example of what it should look like for y = x2 + 2x – 3:

quadratic graph example

Quadratic Graphs and Quadratic Equations

You may be asked to use a graph to solve a quadratic. For example solve the equation 0 = x2 + 2x – 3 using the graph y = x2 + 2x – 3 (shown above).

This is easy! Just look to see where y = 0 on the graph i.e. where the graph crosses the x axis.

So here you can see the answers are -3 and 1.